Merge tag 'pwm/for-4.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry...

[cascardo/linux.git] / drivers / vhost / vhost.c

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 236553e..669fef1 100644 (file)
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -43,11 +43,21 @@ enum {
 #define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num])
 
 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
-static void vhost_vq_reset_user_be(struct vhost_virtqueue *vq)
+static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
 {
        vq->user_be = !virtio_legacy_is_little_endian();
 }
 
+static void vhost_enable_cross_endian_big(struct vhost_virtqueue *vq)
+{
+       vq->user_be = true;
+}
+
+static void vhost_enable_cross_endian_little(struct vhost_virtqueue *vq)
+{
+       vq->user_be = false;
+}
+
 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
 {
        struct vhost_vring_state s;
@@ -62,7 +72,10 @@ static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
            s.num != VHOST_VRING_BIG_ENDIAN)
                return -EINVAL;
 
-       vq->user_be = s.num;
+       if (s.num == VHOST_VRING_BIG_ENDIAN)
+               vhost_enable_cross_endian_big(vq);
+       else
+               vhost_enable_cross_endian_little(vq);
 
        return 0;
 }
@@ -91,7 +104,7 @@ static void vhost_init_is_le(struct vhost_virtqueue *vq)
        vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) || !vq->user_be;
 }
 #else
-static void vhost_vq_reset_user_be(struct vhost_virtqueue *vq)
+static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
 {
 }
 
@@ -113,6 +126,11 @@ static void vhost_init_is_le(struct vhost_virtqueue *vq)
 }
 #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
 
+static void vhost_reset_is_le(struct vhost_virtqueue *vq)
+{
+       vq->is_le = virtio_legacy_is_little_endian();
+}
+
 static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
                            poll_table *pt)
 {
@@ -245,6 +263,13 @@ void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)
 }
 EXPORT_SYMBOL_GPL(vhost_work_queue);
 
+/* A lockless hint for busy polling code to exit the loop */
+bool vhost_has_work(struct vhost_dev *dev)
+{
+       return !list_empty(&dev->work_list);
+}
+EXPORT_SYMBOL_GPL(vhost_has_work);
+
 void vhost_poll_queue(struct vhost_poll *poll)
 {
        vhost_work_queue(poll->dev, &poll->work);
@@ -276,8 +301,9 @@ static void vhost_vq_reset(struct vhost_dev *dev,
        vq->call = NULL;
        vq->log_ctx = NULL;
        vq->memory = NULL;
-       vq->is_le = virtio_legacy_is_little_endian();
-       vhost_vq_reset_user_be(vq);
+       vhost_reset_is_le(vq);
+       vhost_disable_cross_endian(vq);
+       vq->busyloop_timeout = 0;
 }
 
 static int vhost_worker(void *data)
@@ -912,6 +938,19 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
        case VHOST_GET_VRING_ENDIAN:
                r = vhost_get_vring_endian(vq, idx, argp);
                break;
+       case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
+               if (copy_from_user(&s, argp, sizeof(s))) {
+                       r = -EFAULT;
+                       break;
+               }
+               vq->busyloop_timeout = s.num;
+               break;
+       case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
+               s.index = idx;
+               s.num = vq->busyloop_timeout;
+               if (copy_to_user(argp, &s, sizeof(s)))
+                       r = -EFAULT;
+               break;
        default:
                r = -ENOIOCTLCMD;
        }
@@ -1152,14 +1191,14 @@ static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
        return 0;
 }
 
-int vhost_init_used(struct vhost_virtqueue *vq)
+int vhost_vq_init_access(struct vhost_virtqueue *vq)
 {
        __virtio16 last_used_idx;
        int r;
        bool is_le = vq->is_le;
 
        if (!vq->private_data) {
-               vq->is_le = virtio_legacy_is_little_endian();
+               vhost_reset_is_le(vq);
                return 0;
        }
 
@@ -1182,7 +1221,7 @@ err:
        vq->is_le = is_le;
        return r;
 }
-EXPORT_SYMBOL_GPL(vhost_init_used);
+EXPORT_SYMBOL_GPL(vhost_vq_init_access);
 
 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
                          struct iovec iov[], int iov_size)
@@ -1633,6 +1672,20 @@ void vhost_add_used_and_signal_n(struct vhost_dev *dev,
 }
 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
 
+/* return true if we're sure that avaiable ring is empty */
+bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
+{
+       __virtio16 avail_idx;
+       int r;
+
+       r = __get_user(avail_idx, &vq->avail->idx);
+       if (r)
+               return false;
+
+       return vhost16_to_cpu(vq, avail_idx) == vq->avail_idx;
+}
+EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
+
 /* OK, now we need to know about added descriptors. */
 bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
 {